Cryptic Species of Fungal Pathogens Infecting Cicada Nymphs in the Ophiocordycipitaceae

In an ongoing biodiversity study of fungal pathogens on cicada nymphs in Thailand, fifty samples of Pleurocordyceps nipponica-like and Ophiocordyceps longissima-like in Ophiocordycipitaceae were found and collected. The aims of this study were to investigate the biodiversity and to identify the insect pathogenic fungi infecting cicada nymphs within the Ophiocordycipitaceae in Thailand. Our research has encountered challenges and questions arising from cryptic species, making it difficult to identify them based on overlapping morphological characteristics. Both Pleurocordyceps nipponica and Ophiocordyceps longissima are comprised of species complexes, characterized by the production of reddish-brown stromata, mostly branched, and producing red bright-colored cylindrical stroma, respectively. We used a combination of morphological characteristics and molecular data to resolve these two cryptic species. Molecular analysis from multiple gene sequences; SSU, LSU, EF1, RPB1 and RPB2, revealed distinct divergence within species, especially in 18S rDNA sequence insertion variations.  Our findings allowed us to segregate Pleurocordyceps nipponica into 2 subclades and Ophiocordyceps longissima into 4 subclades, which will be proposed as new species from Thailand.